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United States Patent |
6,043,168
|
Colman
,   et al.
|
March 28, 2000
|
Internal and topical treatment system for nonwoven materials
Abstract
A nonwoven web material of polymeric fibers having at least one internal
surfactant and at least one topical surfactant. The internal surfactant is
an organosilicon compound. The topical surfactant is at least one of an
ethoxylated hydrogenated fatty oil, a monosaccharide, a monosaccharide
derivative, a polysaccharide, and a polysaccharide derivative. The
nonwoven web material treated with internal and external surfactants has
improved durability and processability over conventional materials treated
with only internal or topical surfactants.
Inventors:
|
Colman; Charles W. (Marietta, GA);
Marmon; Samuel E. (Alpharetta, GA);
Ning; Xin (Alpharetta, GA);
McDowall; Debra J. (Roswell, GA);
Creagan; Christopher C. (Marietta, GA)
|
Assignee:
|
Kimberly-Clark Worldwide, Inc. (Neenah, WI)
|
Appl. No.:
|
920480 |
Filed:
|
August 29, 1997 |
Current U.S. Class: |
442/118; 264/211; 264/211.14; 442/361; 442/401; 442/414 |
Intern'l Class: |
D01F 001/10 |
Field of Search: |
442/414,401,361,118
264/211,211.14
|
References Cited
U.S. Patent Documents
3580735 | May., 1971 | Shimodio et al.
| |
3632715 | Jan., 1972 | Gowdy et al.
| |
3847676 | Nov., 1974 | Palmer et al.
| |
3918995 | Nov., 1975 | Palmer et al.
| |
4378431 | Mar., 1983 | Brown, Jr.
| |
4396389 | Aug., 1983 | Lofgren.
| |
4413032 | Nov., 1983 | Hartmann et al.
| |
4851284 | Jul., 1989 | Yamanoi et al.
| |
4861539 | Aug., 1989 | Allen et al.
| |
4898700 | Feb., 1990 | Yoshinari et al.
| |
4999245 | Mar., 1991 | Orino et al.
| |
5033172 | Jul., 1991 | Harrington.
| |
5045387 | Sep., 1991 | Schmalz.
| |
5130196 | Jul., 1992 | Nishio et al.
| |
5225263 | Jul., 1993 | Baravian et al.
| |
5277851 | Jan., 1994 | Ford et al.
| |
5300357 | Apr., 1994 | Gardiner.
| |
5429629 | Jul., 1995 | Latimer et al. | 604/378.
|
5456982 | Oct., 1995 | Hansen et al.
| |
5464687 | Nov., 1995 | Sheth.
| |
5582904 | Dec., 1996 | Harrington.
| |
5620788 | Apr., 1997 | Garavaglia et al.
| |
Primary Examiner: Morris; Terrel
Assistant Examiner: Juska; Cheryl
Attorney, Agent or Firm: Pauley Peterson Kinne & Fejer
Claims
We claim:
1. A nonwoven web material comprising:
polymeric fibers comprising at least one internal surfactant and at least
one topical surfactant, said at least one internal surfactant comprising
an organosilicon compound and said at least one topical surfactant
comprising a mixture including an ethoxylated hydrogenated fatty oil and a
compound selected from the group consisting of a monosaccharide, a
monosaccharide derivative, a polysaccharide and a polysaccharide
derivative.
2. A nonwoven web material in accordance with claim 1, wherein said
polymeric fibers are bicomponent fibers.
3. A nonwoven web material in accordance with claim 2, wherein said
bicomponent fibers are formed from polypropylene and polyethylene resins.
4. A nonwoven web material in accordance with claim 1, wherein said topical
surfactant is a mixture of octyl polyglycoside and an ethoxylated
hydrogenated castor oil/sorbitan monooleate mixture.
5. A nonwoven web material in accordance with claim 1, wherein said
internal surfactant comprises an average of less than about 10% by weight
of said polymeric fibers.
6. A nonwoven web material in accordance with claim 1, wherein said topical
surfactant comprises an average of less than about 10% by weight of said
polymeric fibers.
7. A nonwoven web material in accordance with claim 5, wherein said
internal surfactant comprises an average of about 0.3 to about 5.0% by
weight of said polymeric fibers.
8. A nonwoven web material in accordance with claim 6, wherein said topical
surfactant comprises an average of about 0.3 to about 5.0% by weight of
said polymeric fibers.
9. A nonwoven web material in accordance with claim 2, wherein said
bicomponent fibers form a spunbond web.
10. A method for producing a nonwoven web material comprising the steps of:
adding an internal surfactant comprising an organosilicon compound to a
polyolefin resin, forming an organosilicon/polyolefin resin;
processing said organosilicon/polyolefin resin to form a nonwoven web
material; and
applying at least one topical surfactant to said nonwoven web material said
at least one topical surfactant comprising a mixture including an
ethoxylated hydrogenated fatty oil and a compound selected from the group
consisting of a monosaccharide, a monosaccharide derivative, a
polysaccharide and a polysaccharide derivative.
11. A method in accordance with claim 10, wherein said nonwoven web
material is a bicomponent nonwoven web material.
12. A method in accordance with claim 11, wherein said bicomponent nonwoven
web material comprises polypropylene and polyethylene.
13. A method in accordance with claim 10, wherein said topical surfactant
is a mixture of octyl polyglycoside and an ethoxylated hydrogenated castor
oil/sorbitan monooleate mixture.
14. A method in accordance with claim 10, wherein said internal surfactant
is added to said polyolefin resin in an amount up to about 5% by weight of
said polyolefin resin.
15. A method in accordance with claim 10, wherein said topical surfactant
is applied to said nonwoven web material in an amount up to about 5% by
weight of said nonwoven web material.
16. A dual treatment method for improving durability and processability of
nonwoven materials comprising:
adding an internal additive comprising at least one organosilicon compound
surfactant to a polyolefin resin prior to formation of said nonwoven
material; and
adding a topical surfactant comprising a mixture including an ethoxylated
hydrogenated fatty oil and a compound selected from the group consisting
of a monosaccharide, a monosaccharide derivative, a polysaccharide and a
polysaccharide derivative, to a fluid intake side of said nonwoven
materials.
17. A method in accordance with claim 16, wherein said topical surfactant
is a mixture of octyl polyglycoside and an ethoxylated hydrogenated castor
oil/sorbitan monooleate mixture.
18. A limited use or disposable article comprising:
a nonwoven material comprising polymeric fibers comprising at least one
internal surfactant and at least one topical surfactant, said at least one
internal surfactant comprising an organosilicon polymer and said at least
one topical surfactant comprising a mixture including an ethoxylated
hydrogenated fatty oil and a compound selected from the group consisting
of a monosaccharide, a monosaccharide derivative, a polysaccharide and a
polysaccharide derivative.
19. An article in accordance with claim 18, wherein said polymeric fibers
are bicomponent fibers.
20. An article in accordance with claim 18, wherein said bicomponent fibers
are formed from polypropylene and polyethylene resins.
21. An article in accordance with claim 18, wherein said topical surfactant
is a mixture of octyl polyglycoside and an ethoxylated hydrogenated castor
oil/sorbitan monooleate mixture.
22. An article in accordance with claim 18, wherein said article is a
diaper.
23. An article in accordance with claim 18, wherein said article is a
training pants.
24. An article in accordance with claim 18, wherein said article is an
adult incontinent garment.
25. An article in accordance with claim 18, wherein said article is a
medical garment.
26. A nonwoven web material comprising:
polymeric fibers formed from a mixture of a polyolefin resin and at least
one internal surfactant and having at least one topical surfactant
comprising a mixture including an ethoxylated hydrogenated fatty oil and a
compound selected from the group consisting of a monosaccharide, a
monosaccharide derivative, a polysaccharide and a polysaccharide
derivative, said at least one internal surfactant having a capability to
bloom without heating of said polymeric fibers and provide said polymeric
fibers with instantaneous wettability.
27. A nonwoven web material in accordance with claim 26, wherein said at
least one internal surfactant comprises an organosilicon compound.
28. A nonwoven web material in accordance with claim 26, wherein said
topical surfactant is a mixture of octyl polyglycoside and an ethoxylated
hydrogenated castor oil/sorbitan monooleate mixture.
29. A nonwoven web material in accordance with claim 26, wherein said
internal surfactant comprises an average of less than about 10% by weight
of said polymeric fibers.
30. A nonwoven web material in accordance with claim 26, wherein said
topical surfactant comprises an average of less than about 10% by weight
of said polymeric fibers.
31. A nonwoven web material in accordance with claim 29, wherein said
internal surfactant comprises an average of about 0.1 to about 5.0% by
weight of said polymeric fibers.
32. A nonwoven web material in accordance with claim 30, wherein said
topical surfactant comprises an average of about 0.1 to about 5.0% by
weight of said polymeric fibers.
33. A method for producing a nonwoven web material comprising the steps of:
adding an internal surfactant to a polyolefin resin, forming a
surfactant/polyolefin resin mixture;
processing said surfactant/polyolefin resin mixture to form a nonwoven web
material, said internal surfactant blooming within said nonwoven web
material without application of additional heat to said nonwoven web
material, thereby providing said nonwoven web material with substantially
instantaneous wettability; and
applying at least one topical surfactant to said nonwoven web material,
said at least one topical surfactant comprising a mixture including an
ethoxylated hydrogenated fatty oil and a compound selected from the group
consisting of a monosaccharide, a monosaccharide derivative, a
polysaccharide and a polysaccharide derivative.
34. A process in accordance with claim 33, wherein said at least one
internal surfactant comprises an organosilicon compound.
35. A process in accordance with claim 34, wherein said topical surfactant
is a mixture of octyl polyglycoside and an ethoxylated hydrogenated castor
oil/sorbitan monooleate mixture.
36. A process in accordance with claim 33, wherein said nonwoven web
material is a bicomponent nonwoven web material.
37. A process in accordance with claim 36, wherein said bicomponent
nonwoven web material comprises polypropylene and polyethylene.
38. A process in accordance with claim 33, wherein said internal surfactant
is added to said polyolefin resin in an amount up to about 5% by weight of
said polyolefin resin.
39. A process in accordance with claim 33, wherein said topical surfactant
is applied to said nonwoven web material in an amount up to about 5% by
weight of said nonwoven web material.
Description
FIELD OF THE INVENTION
This invention relates to a system for treating nonwoven materials using
topically applied and internally applied treatments to provide improved
durability and processability, particularly compared to nonwoven materials
to which internal or topical treatments alone have been applied. More
particularly, this invention relates to a nonwoven web material comprising
a plurality of polymeric fibers treated with at least one internal
surfactant and at least one topical surfactant whereby the topical
surfactant imparts durable wettability to the nonwoven web material and
the internal surfactant imparts instantaneous wettability to the nonwoven
web material and aids in the application of the topical surfactant.
BACKGROUND OF THE INVENTION
Absorbent personal care articles such as sanitary napkins, disposable
diapers, incontinent-care pads and the like are widely used, and much
effort has been made to improve the effectiveness and functionality of
these articles. These articles generally include a liquid absorbent
material backed by a liquid-impervious barrier sheet. To enhance the sense
of comfort, the absorbent material has a facing of a material which masks
at least the body-facing surface of the product. The purpose of this cover
material is to help structurally contain the absorbent material and to
protect the wearer from continuous direct contact with moisture from
previously wetted absorbent material. The cover material is typically a
relatively low basis weight nonwoven fabric. Improved product performance
has been obtained in these products through the incorporation of a surge
management material disposed between this cover material and the absorbent
material. (See U.S. Pat. No. 5,429,629.) The surge management material is
made from a relatively high basis weight, low density, that is thick,
nonwoven web material. The cover material must, therefore, be permeable to
liquids on the side of the product that is placed against the body,
actively promoting the immediate transfer of each liquid application or
insult through the surge management material and into the absorbent pad.
It is also necessary that the surge management material initially hold the
liquid passed through the cover material and then give up said liquid to
the absorbent material.
In order to satisfy these requirements, it is necessary that the surfaces
of the cover material and surge management material or the surface of the
fibers forming said nonwoven fabrics, be first wetted by the liquid.
Wettability of nonwoven webs or fibers thereof is known to be achievable
by treating the surface thereof with surfactants. See, for example, U.S.
Pat. No. 4,413,032 to Hartmann et al. and U.S. Pat. No. 5,045,387 to
Schmalz. Alternative methods of imparting wettability to such materials
are taught, for example, by U.S. Pat. No. 5,456,982 to Hansen et al. in
which a bicomponent fiber is provided with permanent hydrophilic surface
properties by incorporating a surface active agent into the sheath
component and optionally by including a hydrophilic polymer or copolymer
in the sheath component. See, also, U.S. Pat. No. 5,582,904 to Harrington
which teaches the incorporation into a polyolefin-containing cast or
spin-melt composition for production of nonwoven materials a modifier
composition comprising at least one M,M-polyalkoxylated 10-22 carbon fatty
acid amine, inclusive of amines having 12-20 carbon and preferably 18
carbon linear straight chain moiety corresponding to that found in stearic
or oleic acid, and up to about 60%, including 0.1%-45% by weight of a
modifier composition, of a primary or secondary 10-22 carbon fatty acid
amide, such as stearamide.
We have found, however, that the use only of internal surfactants, which
without a subsequent blooming step impart instantaneous wettability,
results in fabrics that are not durable to multiple insults. By
durability, we mean the ability of the material to withstand multiple
insults. We have also found that a high basis weight, low density
polyolefin web with an internal surfactant is desirable for improving
treatability by a topical surfactant in order to provide good wettability.
Fabrics without an internal surfactant, but which are topically treated
with dilute solutions of surfactants, also exhibit good wettability.
However, this approach is undesirable because a significant amount of
drying is required.
Accordingly, it is one object of this invention to provide a nonwoven web
material having improved durability and processability over conventional
nonwoven materials treated with internal or topical surfactants alone.
It is another object of this invention to provide a dual treatment system,
that is one employing both internal and topical surfactants, for improving
the durability and processability of nonwoven web materials.
It is yet another object of this invention to provide a nonwoven web
material which is instantaneously wettable so as to provide virtually
instantaneous transport of liquids through the web.
SUMMARY OF THE INVENTION
These and other objects of this invention are achieved by a nonwoven web
material comprising polymeric fibers treated by a dual treatment system of
at least one internal surfactant and at least one topical surfactant. The
at least one internal surfactant comprises an organosilicon compound and
the at least one topical surfactant comprises a compound selected from the
group consisting of an ethoxylated hydrogenated fatty oil, a
monosaccharide, a monosaccharide derivative, a polysaccharide, a
polysaccharide derivative, and combinations thereof. In accordance with
one particularly preferred embodiment of this invention, the polymeric
fibers are bicomponent fibers formed from polypropylene and polyethylene
resins.
Such nonwoven web materials are produced by a method in accordance with
this invention in which an internal surfactant comprising an organosilicon
compound is added to a polyolefin resin, forming an
organosilicon/polyolefin resin. The organosilicon/polyolefin resin is spun
into a bicomponent spunbond web. At least one topical surfactant
comprising a compound selected from the group consisting of an ethoxylated
hydrogenated fatty oil, a monosaccharide, a monosaccharide derivative, a
polysaccharide, a polysaccharide derivative, and combinations thereof, is
applied to the intake side of the spunbond web.
The nonwoven web materials of this invention are suitable for use in
limited use or disposable items, that is products and/or components used
only a small number of times, or possibly only once, before being
discarded. Examples of such products include, but are not limited to,
surgical and health care related products such as surgical drapes and
gowns, disposable work wear such as coveralls and lab coats, and personal
care absorbent products such as diapers, training pants, incontinence
garments, sanitary napkins, bandages, wipes and the like.
DEFINITIONS
As used herein, the term "internal surfactant" or "internal treatment"
means a surfactant or treatment that is in the molten polymer during the
extrusion process.
As used herein, the term "topical surfactant" or "topical treatment" means
surfactants or treatments that are applied to formed fibers or fabrics
made from such fibers.
As used herein, the term "nonwoven web" means a web that has a structure of
individual fibers or threads which are interlaid, but not in an
identifiable, repeating manner. Nonwoven webs have been, in the past,
formed by a variety of processes such as, for example, melt-blowing
processes, spunbonding processes, and bonded carded web processes.
As used herein, the term "spunbonded fibers" refers to small diameter
fibers which are formed by extruding a molten thermoplastic material as
filaments from a plurality of fine, usually circular, capillaries of a
spinnerette with the diameter of the extruded filaments then being rapidly
reduced as by, for example, eductive drawing or well-known spunbonding
mechanisms.
As used herein, the term "polymer" generally includes, but is not limited
to, homopolymers, copolymers, such as for example, block, graft, random
and alternating copolymers, terpolymers, etc., and blends and
modifications thereof. Furthermore, unless otherwise specifically limited,
the term "polymer" includes all possible geometric configurations of the
material, including, but not limited to, isotactic, syndiotactic, and
random symmetries.
As used herein, the term "consisting essentially of" does not exclude the
presence of additional materials which do not significantly affect the
desired characteristics of a given composition or product. Exemplary
materials of this sort would include, without limitation, pigments,
antioxidants, stabilizers, waxes, solvents, and particulates.
As used herein, the term "bicomponent fibers" refers to various
configurations including, but not limited to, side-by-side, core and
sheath, pie segments, and islands in the sea configurations.
DESCRIPTION OF PREFERRED EMBODIMENTS
This invention relates to a dual treatment system for improving durability
and processability of nonwoven web materials which combines topical and
internal treatment of the polymeric fibers comprising the nonwoven web
material. This system includes an internal surfactant which is added to
the polyolefin resin utilized to make the nonwoven web, which polyolefin
resin is then spun into the nonwoven web. The internal surfactant is one
which does not require a heating step after its addition to the polyolefin
resin in order to bloom. The internal surfactant provides instantaneous
wettability to the nonwoven web and enhances the ability of the topical
treatment to wet the web. Subsequent thereto, the topical treatment is
applied to the intake side of the base nonwoven web. Whereas the internal
surfactant by itself would have very limited durability, the topical
treatment imparts substantially greater durability to the wettable finish
of the nonwoven web.
Accordingly, a nonwoven web material in accordance with this invention
comprises polymeric fibers comprising at least one internal surfactant and
at least one topical surfactant. The at least one internal surfactant is a
surfactant which blooms without additional heating after its addition to
the polyolefin resin used to make the nonwoven web and preferably
comprises an organosilicon compound. The at least one topical surfactant
comprises at least one of an ethoxylated hydrogenated fatty oil, a
monosaccharide, a monosaccharide derivative, a polysaccharide, and a
polysaccharide derivative. In accordance with a particularly preferred
embodiment, the polymeric fibers are bicomponent fibers formed from
polypropylene and polyethylene resins.
In accordance with one preferred embodiment, the topical surfactant
comprises an average of less than about 10% by weight of said fibers. In
accordance with a particularly preferred embodiment, the topical
surfactant comprises an average of about 0.1% to about 5.0% by weight of
said fibers.
In accordance with one preferred embodiment, the internal surfactant
comprises less than about 10% by weight of the polymeric fibers comprising
the nonwoven web material. In accordance with a particularly preferred
embodiment, the internal surfactant comprises in the range of about 0.1%
to about 5% by weight of the polymeric fibers.
EXAMPLE
An internal surfactant, MASIL.RTM.SF-19, an alkoxylated polysiloxane
available from PPG Industries, Inc., Specialty Chemicals Division, Gurnee,
Ill., the chemical formula of which is as follows:
##STR1##
where R is defined as:
--CH.sub.2 CH.sub.2 CH.sub.2 O--(CH.sub.2 CH.sub.2 O).sub.P --(CH.sub.2
CH[CH.sub.3 ]O).sub.Q --R.sup.1
(R.sup.1 =H or ALKYL)
and X, Y, P and Q are positive integers, which has the ability to lower the
surface tension of water into the range of 20-21 dynes per centimeter from
72 dynes per centimeter at a usage level of about 0.1%, was added to
polypropylene and polyethylene resins which were spun into a bicomponent
spunbond web. This spunbond web was then spray treated with a 3% Ahcovel
Base N-62/Glucopon 220 UP mixture in an active chemical ratio of 3:1.
Ahcovel Base N-62 is a mixture of ethoxylated hydrogenated castor oil and
sorbitan monooleate, the chemical formulas for which are as follows:
##STR2##
available from Hodgson Textile Chemicals, Mount Holly, N.C. and Glucopon
220 UP is an octylpolyglycoside, the chemical formula for which is as
follows:
##STR3##
available from Henkel Corporation, Ambler, Pa. The resulting material was
then evaluated for both wettability and durability, using the Multiple
Insult Simulation Test (MIST) described hereinbelow. These results are
shown in Table 1.
The Multiple Insult Simulation Test measures the amount of liquid (saline
solution) that is held in a material when a specified volume of the liquid
is applied to the material under specified conditions. It also measures
the amount of liquid retained in the material after the liquid insulted
material is placed in contact with an absorbent material, thereby allowing
the liquid to transfer from the test material to the absorbent material.
The test procedure involves calibration of a PUMP to deliver 80 grams of
liquid in 4 seconds (average flow rate of 20 grams per second). A liquid
collection pan is placed on a lab balance beneath the slit in the bottom
of a cradle shaped, non-segmented specimen holder. The balance is then
tared. The specimen to be evaluated, 2.5 inches wide and 7 inches long, is
placed in the bottom of the cradle over a 2.5 inch wide portion of the
slit that is taped to prevent liquid from passing through the part of the
slit directly beneath the specimen. The slit in the bottom of the cradle
runs across the center of the specimen in the direction of the width of
the specimen. The ends of the specimen, in the longer dimension, are
elevated above the center of specimen at approximately 60.degree. from
horizontal. The specimen is insulted by dispensing 80 grams of liquid at a
rate of 20 grams per second directed vertically downward into the center
of the specimen from the end of a fluid application wand held about 0.5
inches above the center of the specimen. The mass of the liquid in the
collection pan is recorded and the balance tared. The specimen is then
removed and placed on a tissue-covered absorbent material. The absorbent
material is composed of a mixture of 60% Favor.RTM. 870 SAM available from
Stockhausen GmbH and 40% wood pulp at a total weight of 500 g/m.sup.2. A
397 gram 2.5 inch by 7 inch plate/weight is placed on top of the specimen
to cover the full area of the specimen for 5 minutes. This procedure is
then repeated 2 additional times. At least two specimens for each material
are tested. The liquid held for each insult divided by the initial weight
of the dry specimen and the liquid retained after each desorption divided
by the initial weight of the dry sample are then calculated.
TABLE 1
__________________________________________________________________________
Liquid Held/
Liquid Held/
Liquid Held/
Liquid Retained
Liquid Retained
Liquid Retained
Treatment
Application 1st Insult
2nd Insult
3rd Insult
Chemistry
Method
Structure
(g/g) (g/g) (g/g)
__________________________________________________________________________
3% A/G
High Solids
3.1
dpf
13.6/0.09
14.8/0.09
15.3/0.11
(3:1 ratio)
Spray 0.025
g/cc
0.7% SF-19
Internal
3.2
dpf
18.0/1.37
17.2/2.21
13.5/1.21
0.021
g/cc
0.7% SF-19
Internal
3.2
dpf
16.9/0.12
17.2/0.45
17.7/0.82
High Solids
3% A/G
Spray 0.021
g/cc
__________________________________________________________________________
Desired Values
>16 g/g liquid held for all three insults
<1 g/g liquid retained for all three insults
Table 1 clearly shows that, while the internal surfactant, 0.70% SF-19,
alone imparts instantaneous wettability, it is not durable to multiple
insults. This is shown by the decrease in liquid held with multiple
insults. In addition, the liquid retained in the specimen after it is
desorbed is above the desired level of 1 g/g.
Table 1 also shows that the polyolefin web without the internal surfactant
does not treat uniformly and, consequently, does not exhibit good
wettability. For example, when treated with 3% Ahcovel/Glucopon (A/G)
using a high solids spray treatment system, the liquid held by the web
material is low, below the desired value of 16 g/g. However, the use of an
internal surfactant in addition to the topical surfactant allows for wet
out of the base nonwoven. For example, a nonwoven web with 0.7% SF-19 in
the bicomponent fiber is treated using a high solids treater with 3%
Ahcovel/Glucopon having a 3:1 ratio of A/G. As shown in the last row of
Table 1, this material showed good initial wettability and improved
durability as well as acceptable levels of liquid retention after
desorption with this combination of treatments compared to treatments with
internal surfactants or topical surfactants alone.
EXAMPLE
A side-by-side bicomponent spunbond was made having 1.25% SF-19 in the
polypropylene side and 0.125% in the polyethylene side. The intake, or
open side, of this fabric was in-line treated with Ahcovel/Glucopon using
a high solids spray treater. The results are summarized in Table 2
hereinbelow.
TABLE 2
______________________________________
Liquid
Held Liquid Held
Liquid Held
Treatment
Application 1st Insult
2nd Insult
3rd Insult
Chemistry
Method (g/g) (g/g) (g/g)
______________________________________
3% A/G Dip/Extract 16.6 17.9 18.1
(3:1) Ratio
0.7% SF-19
Internal 16.9 17.2 17.7
3% A/G High Solids Spray
0.7% SF-19
Internal 18.0 17.2 13.5
______________________________________
The results summarized in Table 2 show that this material has similar
wettability and durability to materials treated with Ahcovel/Glucopon
using a low solids saturation technique (dip/extract) with hexanol as a
wetting agent. However, the dual treatment system of this invention
provides certain advantages over a conventional dip and squeeze process.
In particular, the loft of the web is maintained in this new process
compared to a 15% decrease in loft observed with dip and squeeze
processes. In addition, the treatment system of this invention in which
the topical surfactant is applied by a high solids spray treatment
provides a lower wet pick-up compared to conventional dip and squeeze
processes, thereby lowering drying requirements of the web during
processing which, in turn, reduces production cost.
It will be apparent to those skilled in the art that the dual treatment
system of this invention can be extended to other internal additives as
well as other topical systems, with either other chemistries and/or other
processes. The internal surfactant can be added to either the
polypropylene or the polyethylene side in a side-by-side bicomponent or to
the sheath in a sheath/core configuration. The use of an internal additive
to aid in wetting out of the web in subsequent treatment application
systems may also be done on a spunbond polypropylene web.
This invention is applicable to direct polymer-to-fabric nonwoven
processes, such as single component spunbond and meltblown, in addition to
bicomponent spunbond as discussed hereinabove.
While in the foregoing specification this invention has been described in
relation to certain preferred embodiments thereof, and many details have
been set forth for purpose of illustration, it will be apparent to those
skilled in the art that the invention is susceptible to additional
embodiments and that certain of the details described herein can be varied
considerably without departing from the basic principles of the invention.
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